Digital signage. This is the number 1 application for such displays. You could have a real product at the back and the see-though display at the front displaying some product info and/or promotional videos.
In the picture below, Samsung created a setup with real wine bottles and grapes in the background and a see-through display in the foreground displaying different wines characteristics.

Home use: It would be mainly for space saving and the “woo” effect where you could integrate your TV into your window. For higher end solutions, you could also completely replace your video with one or several (video wall) see-through displays so that your window acts as a TV when it is turned on (no or little transparency) and as a window when it is turned off.

I’m sure they are also other type of applications, I haven’t thought of yet. Let me know your ideas in the comments’ section.

Watch the video below to see such displays in action where Samsung integrated 2 see-through displays in a framed window.